minor #14005 CS: Convert double quotes to single quotes (keradus)

This PR was merged into the 2.3 branch.

Discussion
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CS: Convert double quotes to single quotes

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

Changes generated automatically by upcoming PHP CS Fixer.
To keep fabbot.io happy ;)

Commits
-------

f99c22c CS: Convert double quotes to single quotes

Author: fabpot

Loader/MoFileLoader.php

@@ -88,7 +88,7 @@ private function parse($resource)
         $stat = fstat($stream);
 
         if ($stat['size'] < self::MO_HEADER_SIZE) {
-            throw new InvalidResourceException("MO stream content has an invalid format.");
+            throw new InvalidResourceException('MO stream content has an invalid format.');
         }
         $magic = unpack('V1', fread($stream, 4));
         $magic = hexdec(substr(dechex(current($magic)), -8));
@@ -98,7 +98,7 @@ private function parse($resource)
         } elseif ($magic == self::MO_BIG_ENDIAN_MAGIC) {
             $isBigEndian = true;
         } else {
-            throw new InvalidResourceException("MO stream content has an invalid format.");
+            throw new InvalidResourceException('MO stream content has an invalid format.');
         }
 
         // formatRevision

PluralizationRules.php

@@ -31,9 +31,9 @@ class PluralizationRules
      */
     public static function get($number, $locale)
     {
-        if ("pt_BR" == $locale) {
+        if ('pt_BR' == $locale) {
             // temporary set a locale for brazilian
-            $locale = "xbr";
+            $locale = 'xbr';
         }
 
         if (strlen($locale) > 3) {
@@ -197,9 +197,9 @@ public static function get($number, $locale)
      */
     public static function set($rule, $locale)
     {
-        if ("pt_BR" == $locale) {
+        if ('pt_BR' == $locale) {
             // temporary set a locale for brazilian
-            $locale = "xbr";
+            $locale = 'xbr';
         }
 
         if (strlen($locale) > 3) {